| 1. |
- Belitsky, Victor, 1955, et al.
(författare)
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Facility Heterodyne Receiver for the Atacama Pathfinder Experiment Telescope
- 2007
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Ingår i: Proceedings of Joint 32nd International Conference on Infrared Millimeter Waves and 15th International conference on Terahertz Electronics, Sept 3-7, 2007, City Hall, Cardiff, Wales, UK. ; , s. 326-328
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Konferensbidrag (refereegranskat)
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| 2. |
- Chiavari, C, et al.
(författare)
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Atmospheric corrosion of historical organ pipes: The influence of environment and materials
- 2008
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X. ; 50:9, s. 2444-2455
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Tidskriftsartikel (refereegranskat)abstract
- The corrosion of lead-rich pipes in historical organs in different parts of Europe has been investigated. The influence of the environment and the composition and microstructure of the pipe metal was studied. Pipe Corrosion was documented by visual inspection (boroscope). The corrosion attack and the composition and microstructure of the metal were characterized by OM, SEM, XRD, IC and FAAS. It is shown that the degree of corrosion of the pipes is correlated to the concentration of gaseous acetic and formic acid in the organ. The organic acids are emitted by the wood from which the wind system is built. It is also shown that pipe corrosion decreases with increasing tin content in the range 0-4% (wt). Possible conservation strategies are discussed. (c) 2008 Elsevier Ltd. All rights reserved.
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| 3. |
- Giorgi, R., et al.
(författare)
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Nanoparticles of calcium hydroxide for wood deacidification: Decreasing the emissions of organic acid vapors in church organ environments
- 2009
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Ingår i: Journal of Cultural Heritage. - : Elsevier BV. - 1296-2074 .- 1778-3674. ; 10:2, s. 206-213
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Tidskriftsartikel (refereegranskat)abstract
- Acetic and formic acid vapors emitted from woodwork in historical organs are very important corrosive agents for lead pipes. These acids are slowly released from the wood both during playing and when the pipes are silent. To inhibit this emission process. the wood surface can be modified, by creating a protective layer with alkaline features. However, a coating of wood is not recommended since this could modify the appearance and create a layer not perfectly compatible with the substrate. For this reason, we propose to use some innovative nanotechnology that has been successfully applied for the deacidification of wood samples coming from the Vasa shipwreck. Application of calcium (or magnesium) hydroxide nanoparticles, with sizes ranging from 30-150 nm, allowed a homogeneous distribution of particles through the surface layer of wood simply by soaking (or spraying) it in a alcohohc (or mixed with less polar solvents) dispersion of nanoparticies. Nanoparticles do not modify the wood appearance and distribute randomly within the first layers of wood. The small size of particles accounts for the high reactivity with CO2 from the air, to give the alkaline reserve of carbonates that provide high efficacy in the neutralization of gaseous acids. The emission of volatile organic compounds (VOC) from the treated wood was determined by using an emission test cell, Field and Laboratory Emission Cell (FLEC). The results show that the emissions of acetic acid vapor from nanoparticles treated wood was very low (
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| 4. |
- Inganaes, Olle, et al.
(författare)
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Alternating fluorene copolymer-fullerene blend solar cells
- 2005
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Ingår i: Optical Science and Engineering. ; 99, s. 387-402
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Tidskriftsartikel (refereegranskat)abstract
- We present a new class of alternating fluorene copolymers, which can be combined with a fullerene acceptor, to make polymer blends suitable for photovoltaic energy conversion. By choice of comonomers in the polymer, it is possible to engineer the optical absorption spectrum and to cover the wavelength range down to 900 nm. The transport properties of the polymers investigated so far are competitive with other polymers used in polymer solar cells and the mixing of polymers with acceptors in the form of fullerenes is extensive. These polymers are therefore of interest in the future developments of high-performance polymer solar cells. [on SciFinder (R)]
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| 5. |
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| 6. |
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| 7. |
- Niklasson, Annika, 1977, et al.
(författare)
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Air Pollutant Concentrations and Atmospheric Corrosion of Organ Pipes in European Church Environments
- 2008
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Ingår i: Studies in Conservation. - 0039-3630 .- 2047-0584. ; 53:1, s. 24-40
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: The atmospheric environment inside and outside historical organs in several European regions is reported. In each region, comparisons were made between an instrument suffering organ pipe corrosion and an organ without corrosion problems. Concentrations of acetic acid (ethanoic acid), formic acid (methanoic acid), acetaldehyde (ethanal), formaldehyde (methanal) and other volatile organic compounds in the organ environment were determined using active sampling. Temperature and relative humidity were recorded. In addition, polished metal samples that mimic the material used in the historical organ pipes have been exposed in the organ wind systems for up to 22 months. High concentrations of acetic acid and formic acid vapours are present in the wind system of the corroded organs. Acetaldehyde and formaldehyde are also present in smaller amounts. The main source of acetic acid is the wood from which the wind system is built. In contrast, formic acid is generated in the chruch environment outside the wind system. The results show that the two organic acids play an important role in the atmospheric corrosion of organ pipes. It is suggested that the corrosion of lead pipes in historical organs can be effectively reduced by removing the sources of gaseous acetic acid and formic acid in the wind system and in the chruch environment.
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| 8. |
- Niklasson, Annika, 1977, et al.
(författare)
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Atmospheric corrosion of lead - The influence of formic acid and acetic acid vapors
- 2007
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Ingår i: Journal of the Electrochemical Society. - 1945-7111 .- 0013-4651. ; , s. 618-625
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Tidskriftsartikel (refereegranskat)abstract
- The present laboratory study investigates the influence of low concentrations of formic acid vapor and the combination of acetic and formic acid vapors on the atmospheric corrosion of lead. The samples were exposed to synthetic air with careful control of relative humidity (95%), temperature (22.00 degrees C), flow conditions and the concentration of formic acid (160 ppb), acetic acid (170 ppb) and CO2 (350 ppm). Exposure time was one, two and four weeks. Corrosion products were analyzed by gravimetry, ion chromatography, quantitative carbonate analysis, X-ray diffraction and environmental scanning electron microscopy. Cross sections of the corroded surface were prepared by focused ion beam milling. Formic acid vapor is very corrosive toward lead, although somewhat less so than acetic acid. The corrosion products, consisting of plumbonacrite (Pb10O(OH)(6)(CO3)(6)) and lead formate hydroxide [Pb(HCOO)(OH)], are evenly distributed. The combination of acetic and formic acid has a synergistic effect on lead corrosion. The corrosion products found were plumbonacrite and massicot (beta-PbO) together with an unidentified phase. Corrosion attack in the mixed pollutant exposure is more localized compared to the acetic and formic acid exposures, clearly indicating the electrochemical nature of corrosion.
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| 9. |
- Niklasson, Annika, 1977, et al.
(författare)
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Influence of acetic acid vapor on the atmospheric corrosion of lead
- 2005
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 152:12, s. B519-B525
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Tidskriftsartikel (refereegranskat)abstract
- The present study investigates the influence of low concentrations of acetic acid vapor on the atmospheric corrosion of lead. The samples were exposed to synthetic air with careful control of relative humidity (95%), temperature (22.00 degrees C), acetic acid concentration (170-1100 ppb), CO2 concentration (350 ppm), and flow conditions. The exposure times were between 1 and 4 weeks. Mass gain results are reported. The corrosion products were analyzed by ion chromatography, quantitative carbonate analysis, and X-ray diffraction. The surface morphology of the exposed samples was investigated with environmental scanning electron microscope. The results show that low concentrations of acetic acid vapor are very corrosive toward lead. The mass gain is linear with time and depends linearly on the acetic acid concentration. It is suggested that the corrosion of lead in the presence of traces of acetic acid vapor is electrochemical in nature. The corrosion products found were plumbonacrite, Pb10O(OH)(6)(CO3)(6), lead acetate oxide hydrate (Pb(CH3COO)(2)center dot 2PbO center dot H2O), and lead oxide, PbO. (c) 2005 The Electrochemical Society.
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| 10. |
- Oertel, CM, et al.
(författare)
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Acetic Acid Vapor Corrosion of Lead-Tin Alloys Containing 3.4 and 15% Tin
- 2009
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 1945-7111 .- 0013-4651. ; 156:12, s. C414-C421
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Tidskriftsartikel (refereegranskat)abstract
- Lead-tin alloy pipes in historic organs frequently suffer from damaging atmospheric corrosion. Organic acids emitted from the wood of organ cases had been established previously as the cause of deterioration in pure lead pipes. In the present study, lead-tin alloy samples containing 3.4 and 15 atom % tin were subjected to laboratory exposure experiments under atmospheres of 1100 ppb acetic acid, 350 ppm CO2, and 60 or 95% relative humidity (RH). Wet and dry corrosion mass gains were monitored, and corrosion product compositions and morphologies were characterized by grazing incidence angle X-ray diffraction and scanning electron microscopy. Cross sections were cut through corrosion sites using a focused ion beam milling method, and elemental information was obtained using wavelength dispersive and energy dispersive X-ray analyses. The corrosion products and morphologies observed in the alloys are the same as those reported for pure lead, but the corrosion susceptibilities of the alloys show a much stronger dependence on RH. The presence of 3.4 or 15 atom % Sn provides corrosion protection at moderate humidity, but this protective effect breaks down at high humidity. These findings highlight the importance of humidity control as well as pipe material selection in the conservation of historic and newly constructed organs.
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| 11. |
- Oertel, CM, et al.
(författare)
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Focused ion beam and electron microscopy analysis of corrosion of lead-tin alloys: Applications to conservation of organ pipes
- 2008
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Ingår i: Materials Research Society Symposium Proceedings. - 0272-9172. - 9781558999886 ; 1047, s. 115-125
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Tidskriftsartikel (refereegranskat)abstract
- Across Europe, lead-tin alloy organ pipes are suffering from atmospheric corrosion. This deterioration can eventually lead to cracks and holes, preventing the pipes from producing sound. Organ pipes are found in compositions ranging from >99% Pb to >99% Sn. For very lead-rich (>99% Pb) pipes, organic acids emitted from the wood of organ cases have previously been identified as significant corrosive agents. In order to study the role of alloy composition in the susceptibility of pipes to organic acid attack, lead-tin alloys containing 1.2-15 at.% Sn were exposed to acetic acid vapors in laboratory exposure studies. Corrosion rates were monitored gravimetrically, and corrosion product phases were identified using grazing incidence angle X-ray diffraction. In a new method, focused-ion beam (FIB) cross sections were cut through corrosion sites, and SEM and WDX were used to obtain detailed information about the morphology and chemical composition of the corrosion layers. The combination of FIB and SEM has made it possible to obtain depth information about these micron-scale layers, providing insight into the influence of acetic acid on alloys in the 1.2-15 at.% Sn range.
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| 12. |
- Olofson, K. Frans G., 1976, et al.
(författare)
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Arctic aerosol and clouds studied by bistatic lidar technique
- 2009
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Ingår i: Journal of Geophysical Research. - Washington, D.C. : American geophysical union. - 0148-0227 .- 2156-2202. ; 114, s. D18208-
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Tidskriftsartikel (refereegranskat)abstract
- Aerosol and cloud studies were carried out with a polarimetric bistatic lidar setup at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) in Andenes (69°N, 16E°), Norway. The measurements were performed from 10 to 23 October 2006 and covered altitudes between 1.5 and 11 km, corresponding to scattering angles between 130 and 170°. The degree of linear polarization, PL, calculated from the experiments was compared with light scattering calculations using Lorenz‐Mie theory for spherical particles, the T‐matrix approach for nonspherical rotationally symmetric particles, and a geometric optics ray‐tracing method. Average PL values between 0.61 and 0.72 were obtained for the background aerosol under cloud‐free conditions. The aerosol results may be qualitatively reproduced by standard aerosol types if a suitable combination of coarse‐ and fine‐mode spherical particles is assumed. The PL values obtained for thin and mildly opaque clouds were in the range from 0.21 to 0.38. These results were not well described by spherical particles, and the results for relatively small prolate and oblate particles studied with the T‐matrix method tended to be slightly higher than the experimental values. Geometric optics calculations for hexagonal column ice particles with surface roughness were able to reproduce the experimental cloud data. This does not rule out contributions from other types of particles, and particle orientation effects may also have influenced the results. We conclude that the experimental results are consistent with earlier in situ studies of cirrus clouds, and the further development and application of the bistatic lidar technique is discussed.
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| 13. |
- Romero Lejonthun, Liza, 1973, et al.
(författare)
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Formation of Adsorbed Layers by Deposition of Dinitrogen Pentoxide, Nitric Acid, and Water on Graphite
- 2009
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Ingår i: J. Phys. Chem. C. - : American Chemical Society (ACS). ; 113, s. 7728-7734
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Tidskriftsartikel (refereegranskat)abstract
- The formation of adsorbed layers of dinitrogen pentoxide, nitric acid, and water on graphite has been studied by molecular beam and light-scattering techniques. The desorption kinetics of N2O5 on graphite were described by the Arrhenius equation with an activation energy of 0.24 ± 0.03 eV and a pre-exponential factor of 2.3 × 10(10 ± 0.73) s−1, and N2O5 is concluded to bind more strongly than H2O to the graphite surface. Elastic helium scattering and light scattering were used to probe the formation of adlayers on the surface. Adsorption of pure N2O5 resulted in formation of thin adlayers at temperatures below 160 K. In coadsorption experiments N2O5 was concluded to facilitate the formation of thick N2O5−H2O ice layers at 155 K. In a similar way coadsorption of HNO3 and H2O resulted in the formation of thick adlayers at 170 K. N2O5 and HNO3 both bind more strongly than water to the graphite surface and are concluded to facilitate nucleation and growth of ice.
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| 14. |
- Sundin, Erik, 1974-, et al.
(författare)
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Solvent-free Industrial Cleaning of Printed Circuit Boards
- 2009
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Ingår i: Proceedings of EcoDesign 2009, Sapporo, Japan. - 9784888981927 ; , s. 823-828
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Konferensbidrag (refereegranskat)abstract
- The manufacturing industry today uses different kinds of chemicals in its cleaning processes. The industrial cleaners often contain some sort of degreasing chemical to clean parts and components before for instance sur-face treatment processes. These types of cleaning meth-ods imply expensive and dangerous handling of chemi-cals in the manufacturing process, as well as in the transportation of hazardous waste. Furthermore, the cleaning processes also use a substantial amount of en-ergy for cleaning.The aim of this paper is to explore the potential of how ultra-clean water cleaning can be used in the manufac-turing industry. In order to meet the aim, a case study was conducted at a electronic manufacturer. The data for this research was collected mainly through interviews, but also by industrial study visits.The results from this research show that using solvent-free industrial cleaning with ultra-clean water is benefi-cial from the perspectives of quality, environment and business. The quality improvement is the most important benefit that the electronic manufacturer can see by using solvent-free industrial cleaning for their printed circuit boards.
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| 15. |
- Svensson, Erik, 1977
(författare)
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Experimental studies of ice particle formation with tropospheric relevance
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In their fourth assessment report, the Intergovernmental Panel on Climate Change points out the influence of particles suspended in air, known as an aerosol, as the main uncertainty in the understanding of the climate system. Aerosols affect climate in a number of ways. The so-called direct effect is due to scattering and absorption of light passing through the atmosphere. The indirect effects are caused by aerosol-cloud interactions. The formation of clouds requires pre-existing particles for the water vapor to condense onto. The number concentration, size distribution and chemical properties, as well as the atmospheric dynamics, determine the development of a cloud. Clouds reflect incoming solar radiation into space, but also trap heat radiation from the ground. Ice formation in clouds affects their interaction with radiation, their lifetime, and it may induce the formation of precipitation. Cloud droplets can be supercooled to very low temperatures, and droplets of pure water freeze by homogeneous nucleation at temperatures below -33°C. However, droplet freezing can be facilitated by solid particles, a process called heterogeneous freezing. This thesis presents results from laboratory studies of ice formation processes of atmospheric relevance. The overall aim has been to improve the understanding of ice cloud microphysics. An electrodynamic balance was developed and used to study freezing of single levitated droplets in the micrometer size range. Evaporation freezing of oxalic acid solution droplets was investigated at temperatures from 236 to 248 K. Freezing was observed in the whole temperature range, but at the higher temperatures freezing took place after a period of droplet evaporation. The process was explained by the formation of oxalic acid precipitates as the droplets evaporated, which in a subsequent step induced freezing. The potential importance of the process in atmosphere is currently unknown, but it may explain observed freezing in evaporating cloud and further studies should elucidate if the process is a general phenomenon for a large group of compounds. The same setup was also used to study freezing induced by kaolinite particle in collisions with pure water droplets. One or a few collisions were usually sufficient to induce freezing at temperatures from 240 to 268 K, and relative humidity was observed to be important for the freezing efficiency. Aerosol and cloud studies were carried out with a bistatic lidar at the ALOMAR research facility in Andenes, Norway. The degree of linear polarization calculated from the experiments was compared with different types of light scattering calculations. Aerosol results obtained below 3.6 km could only be explained by non-spherical particles. The results obtained for thin clouds could be simulated by ice particles with a certain degree of surface roughness. The bistatic lidar method may provide a useful technique for the development of an improved cirrus cloud climatology and it may be used to validate other techniques. Additional laboratory experiments were carried out to study ice formation on graphite, which was used as a proxy for soot particles in the atmosphere. The presence of dinitrogen pentoxide and nitric acid was concluded to facilitate the growth of thick ice layers and the process was sensitive to temperature and gas deposition rate. The experiments provide an improved molecular level understanding of ice formation, and a starting point for further research on systems of increased complexity.
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| 16. |
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| 17. |
- Svensson, Jenny, 1977-
(författare)
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The Regulation of Rule-Following : Imitation and Soft Regulation in the European Union
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Present times are sometimes referred to as "the golden era of regulation", as more and more areas of social life are regulated. But regulation is not only increasing; it is also changing. New regulators are emerging, and they are issuing new kinds of rules. These new kinds of regulation are frequently not legally binding, and are therefore labelled soft regulation as opposed to hard law. It is not compulsory to follow soft rules but many actors - including sovereign states - still do, and the thesis asks the question why this is so. Why do even states, which are powerful regulators themselves, abide by soft regulation, and wherein lies the regulative power of soft rules? Through an in-depth study of the European Union's pre-accession instrument Twinning an answer to the question of the power of soft regulation has been arrived at. Treating Twinning as a critical case of soft regulation, and using theories of imitation to grasp the meaning and evolution of Twinning projects, makes it possible to define three regulative elements involved in soft regulation. These are the combinative, co-productive and constitutive elements of soft regulation, from which the thesis suggests that it derives its power. First of all, soft regulation combines different kinds of rules, the regulation of identity and the regulation of activity, and a variety of sources of legitimacy. Second, it depends on regulators and regulatees interacting to co-produce regulation. And third, as its main result, it constitutes the rule-followers as formal, rational, and modern organisations. Accordingly, soft regulation has rather impressive regulative capabilities, builds on complex, dynamic, and social interactions, and embodies as well as promotes some of Western society's most strongly institutionalised ideas. The thesis argues that it is through these characteristics that actors, including states, are compelled to follow soft rules.
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